1. Field of the Invention
The present invention relates generally to a mobile data service. In particular, the present invention relates to a radio packet data terminal and a method of determining an Internet interworking protocol address which use added options according to the existence/nonexistence of an Internet packet data terminal identifier of the terminal when a packet data service is requested for an Internet connection under the support of a radio packet data service network structure and a packet data communication protocol.
2. Description of the Related Art
According to the mobile data service recently proposed, an interworking function device (IWF) having a switching function in accordance with a service option set in a mobile terminal is connected to a mobile switching center (MSC), and protocol stacks for other circuit data and packet data are additionally connected to respective network elements of the existing mobile telephone network, so that a circuit data service and packet data service such as asynchronous data and 3G facsimile data can be provided.
FIG. 1 is a schematic block diagram illustrating the structure of a conventional radio data service network.
Referring to FIG. 1, the conventional radio data service network is basically provided with a mobile switching center (MSC) 50 for connecting a call to an interworking function device (IWF) 60 if a mobile subscriber requests a mobile data service in a mobile communication network, and the interworking function device (IWF) 60 for determining a mobile data path by identifying the existence/nonexistence of idle resources after allocating an effective channel of a trunk for data communication, and supporting the data communication between the subscribers. Here, PDN1 and PDN2 are two divided sections of the radio PCS data network.
According to the conventional radio data service, if the radio packet data service or circuit data service is requested from a personal computer 10 or 20 connected to a mobile terminal 11 or 21 to Internet, the mobile terminal 11 or 21 requests a packet call to the mobile switching center 50 with the addition of a service option for the corresponding service.
The packet call of the mobile terminal 11 or 21 is transferred to the mobile switching center 50 through a base transceiver station 30 or 31 and a base station controller 40 or 41. At this time, if the mobile switching center 50 identifies the data service requested by the mobile terminal 11 or 21 and requests a call connection to the interworking function device 60, the interworking function device 60 optionally connects the present call of the mobile terminal 11 or 21 to a public switched telephone network (PSTN)/packet network 70.
As described above, if the mobile terminal 11 or 21 requests the data service only with the addition of the radio data service option in the mobile communication system, the interworking function device 60 determines the data communication path according to the present location of the radio data terminal so that the radio data terminal connects with the radio data service network.
Since the communication path between the mobile terminal and the interworking function device is determined in accordance with the present location of the mobile terminal, if the mobile terminal moves into an area served by a new interworking function device and a handoff is generated during the packet data service, the re-registration procedure for disconnecting the mobile terminal from the previous interworking function device and connecting the mobile terminal to the new interworking function device is required.
As described above, since the conventional mobile terminal for radio data communication is connected to the interworking function device in accordance with the present location of the mobile terminal when the packet data service is requested, if a handoff is generated during the registration of a mobile Internet protocol service, the Internet interworking protocol address should be re-registered. Also, the mobile terminal cannot be directly connected to a specified interworking function device in accordance with the request of the Internet service provider or the Internet user.
Accordingly, the present invention is directed to a radio packet data terminal and a method of determining an Internet interworking protocol address that substantially obviate one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a radio packet data terminal and a method of determining an Internet interworking protocol address which can easily provide a mobile Internet protocol service and a mobile Internet service by adding a packet data service option and an Internet protocol address option to an originating message to be transmitted to a base transceiver station or by adding information on the system address for interworking packet data to be connected, the present state of the packet data connection, the purpose of the packet data service connection, etc., to the originating message, when the radio packet data service for connecting with Internet is requested.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims thereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the radio packet data terminal comprises a first mobile terminal determined by a simple interworking protocol (SIP) option for providing a mobile data service only to a network interworking protocol (IP) after connecting with Internet if the radio packet data terminal does not have a fixed IP address, a second mobile terminal determined by a mobile interworking protocol (MIP) option for providing the mobile data service to a radio LAN port including a home agent and a foreign agent if the radio packet data_terminal has the fixed IP address or is connected to a personal computer (PC), and a third mobile terminal determined by a unique interworking protocol (UIP) option for providing the mobile data service to its own interworking function device if the radio packet data terminal is permanently provided with an Internet interworking protocol.
In another aspect of the present invention, there is provided a method of determining an Internet interworking protocol address comprising the steps of transmitting mobile station packet calls from a mobile terminal to a radio network controller and registering as a packet data service option of the mobile terminal one of a simple interworking protocol (SIP) option, a mobile interworking protocol (MIP) option, and a unique interworking protocol (UIP) option in accordance with a response to the transmitted mobile station packet calls, determining a point-to-point (PPP) link by calling data service packets in accordance with the IP option registered in the mobile station after the registration of the packet data service option and releasing a packet channel of the mobile station if a term of a PPP link timer of a radio network controller expires and a present state is a dormant-open state, and re-determining the open PPP link by transmitting again the mobile station packet calls to a new radio network controller and transmitting an upper layer data on a virtual network pipeline (VNP) if a handoff is generated between the mobile station and the new radio network controller in the dormant-open state of the PPP link.